Audiophile USB to PCM


I have an excellent upsampler and dac (dCS Purcell/Delius) and am looking for the very best USB to PCM conversion. So far, I've tried SlimDevices Squeezebox, and Xitel Pro Hi-Fi link.

Both are very good, but I was wondering if there are any other options I should be considering. Both the Sutherland USB Preamp and the Wavelength USB Dac convert to analog. I'd like something of similar quality that stops short of the digital to analog conversion so that I can let the dCS gear do that.

Any suggestions would be appreciated.

harry
hbrandt
Rk_t, Empirical Audio's web site (Audioengr in this thread) suggests that one should use Foobar software to upconvert to 24/96, because it allegedly is better than hardware upsampling. There may be other software that upconverts to 24/192?

At the moment, what you suggest seems like the way to go: PC card outputting upsampled digital via AES/EBU, with card driven by DAC wordclock. As long as the card is not processing the signal, only outputting an upconverted but otherwise untainted PCM signal from disk. Seems like a better solution than a USB-to-digital converter that is not driven by a wordclock. I'm new at this, so if anyone disagrees or has the best way to go from PC to DAC, I'd also appreciate the suggestions.
I'd be interested in hearing from Audioengr, I'm curious how anyone can make the blanket statement that foobar's upsampling is better than hardware upsampling... Don't get me wrong, I love foobar. But, foobar is a piece of software written for consumer processors. High end companies like dCS and Theta have access to the same body of knowledge used to create the algorithms for foobar, plus the ability to use custom, specific purpose ASICs in hardware decoding that I have to believe can contribute to better upsampling...

That said, I've never run my foobar at 24/96. FBOW, I don't think my Waveterminal will pass 24/96. But, I've been quite happy with audio quality of my Waveterminal into a dCS Purcell/Delius combo...
Edsilva - I mod a LOT of different DAC's, and upsampling engines, including the P-1A, Benchmark DAC-1 and the DIP, so I get to hear the output quality of these hardware and firmware upsamplers.

The Secret Rabbit Code (SRC) upsampler with Foobar2000 is simply the best that I have heard, when played through my Off-Ramp converters. Software upsampling will always be more flexible for generating upsampling algorithms. Hardware and firmware implementations have limitations that software does not have. These algorithms are not trivial to implement in hardware, even using DSP engines.

Steve N.
Empirical Audio
Manufacturer/modder
Interesting--glad you chimed in. Maybe I'll look at my Waveterminal again to see if it is capable of something better than 16/44 and give it a go.

I'm still a bit puzzled by the "why," however. In my admittedly simplistic view, you need software and hardware. Sure, PC software is pretty flexible, but so is a lot of firmware; I upgrade various bits of it across my network all the time. And, I think most processors these days are built to be upgradeable with software downloads.

I concur that the collective minds of sourceforge may have built a better algorithm with SRC; I just don't know. But, you still have the hardware issue...

I guess I think of a PC like a good mass market "please everyone" car like a Honda Civic. Sure, you can tack on some upgrades, open up the intake and exhaust, put on better rubber, tweak the CPU, and you might end up with a pretty quick car that might even beat something labeled as a sports car, like a BMW coupe. You can go even further, rip out the excess weight in the interior, implement engine upgrades, install nitrous, tweak the suspension, improve the aerodynamics, and maybe end up with a car that will take a real sports car, like a Carrera. But, I just have a hard time seeing one of those street racers take on something built from the ground up, no compromise, as a sports car like the Lotus Elise or a Dodge Viper.

Anyway, that was my thinking. Perhaps computers and cars aren't a good analogy. Anyway, guess if my WT24 will pass 24/96, I'll find out...
How is transit stock? Pretty good quality?

It only has Toslink out - not so great.

Why is the mod necessary and how do we do it?

The mod changes the Toslink to coax, improves the edge-rates, isolates with a pulse transformer and matches the impedance precisely. It also adds a modified Superclock3. Quite technical, this mod, and a LOT of surface-mount work.

Also, can you explain how to upsample in foobar or itune?

This is explained on the computer audio page of my website:
http://www.empiricalaudio.com

Do they do it automatically, or do we have to do something?

You have to select resampling in Foobar preferences - see the website for instructions and screen-shots.

Steve N.
Empirical Audio
Manufacturer/modder